JP2003309304A - Method for manufacturing actuator and ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an elongated actuator having a large area utilizing a monocrystal piezoelectric film or a single-orientation polycrystal film, and to provide a method for manufacturing an ink jet head. <P>SOLUTION: The monocrystal piezoelectric film is formed on a bonded monocrystal substrate (preferably, a ZrO<SB>2</SB>substrate that is doped with MgO, STO, BaTiO<SB>3</SB>, and Y or rare earth), after it is bonded to a diaphragm structure member, a crystal substrate is removed, and the actuator or the ink jet head is manufactured. When the superior device can be manufactured by using the object, having surface roughness Ra of 15 nm or less as measured via a bonding part of the bonded substrate is utilized for manufacturing the ink jet head, the head with high-density and a large area having proper characteristics can be obtained. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an actuator and an inkjet head, in which a piezoelectric film on a single crystal substrate is bonded to a vibrating plate structure and the single crystal substrate is removed. . In particular, the present invention relates to a manufacturing method that is effective when manufacturing a large-area actuator and an inkjet head. Further, it is a manufacturing method capable of manufacturing an actuator and an inkjet head having a large area and high density. For example, piezoelectric / electrostrictive film type devices, especially inkjet print heads, microphones, sounding bodies (speakers, etc.), various vibrators and oscillators, and bending displacement of unimorph type and bimorph type used for sensors, etc. It can be preferably used in a method of manufacturing a piezoelectric / electrostrictive film type element of the type to be generated. The element referred to herein means an element that converts electrical energy into mechanical energy, that is, mechanical displacement or stress or vibration, and an element that performs the opposite conversion.

[0002]

2. Description of the Related Art In recent years, in the fields of optics and precision processing, a displacement element for adjusting the optical path length and position on the order of submicrons and a detection element for detecting a minute displacement as an electrical change have been desired. In response to this, an actuator that uses an inverse piezoelectric effect or a displacement based on the electrostrictive effect that occurs when an electric field is applied to a ferroelectric piezoelectric / electrostrictive material, or an opposite phenomenon, Piezoelectric / electrostrictive elements such as sensors and sensors are being developed.

By the way, in an ink jet print head or the like, such a piezoelectric / electrostrictive element structure is
The conventionally known unimorph type and bimorph type are
It is preferably used. Then, there is a demand for improvement in printing quality, printing speed, etc. of printers using such elements, and in order to meet such demand, miniaturization, high density and low voltage driving of such piezoelectric / electrostrictive film type elements are required. Development is underway to achieve high-speed response and long nozzles.

In these unimorph type and bimorph type piezoelectric / electrostrictive elements, it is important to reduce the thickness of the substrate to be the vibrating plate in order to obtain a large bending displacement, a generated force or a generated potential. However, if the thickness of the substrate is reduced, there is a problem that the strength is lowered and the smoothness is lowered. In addition, in the conventional unimorph type or bimorph type piezoelectric / electrostrictive element, there is a problem that reliability is impaired because an adhesive is used.

In order to overcome them, Japanese Patent Laid-Open No. 62-213399
Japanese Patent Laid-Open Publication No. 2003-242242 discloses a technology for a piezoelectric speaker, in which a piezoelectric ceramic and a ceramic diaphragm are simultaneously sintered to provide strong bonding strength. However, since this method sinters dissimilar materials at high temperatures,
There are problems that it is difficult to optimize the design because the selection of the diaphragm is limited and that the diaphragm and the piezoelectric ceramics themselves contract, so that it is difficult to match the dimension accuracy of the micron order in a large area. Therefore, it is difficult to obtain a highly reliable large-area piezoelectric / electrostrictive element (actuator) or an inkjet head. Further, as a method for producing an inkjet head by producing a single crystal piezoelectric film in order to obtain a higher density head, there is disclosed in Japanese Patent Laid-Open No. 11-348285.
No. In Japanese, a single crystal PbTiO ₃ deposited on the single crystal Pb (Zr,
Although a method of using Ti) O ₃ for an inkjet head is described, the denseness of the vibration plate formed on the piezoelectric film is poor, and a head with good durability cannot be obtained. Further, Japanese Patent Laid-Open No. 2001-113712 describes a method of manufacturing a long inkjet head using a plurality of single crystal MgO substrates. However, with this method, it was impossible to fabricate a high-density head because of the gap between the substrates that occurs when the substrates are arranged. In addition, since a large-area single crystal MgO substrate cannot be stably manufactured, it is not possible to use a single-crystal or single-oriented crystal piezoelectric film formed on a single-crystal substrate for a large-area actuator and inkjet head. It was possible.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel manufacturing method suitable for a piezoelectric / electrostrictive film type element, particularly an actuator and an ink jet head, which solves the above problems. In particular, it is an object of the present invention to provide a large-area and long-sized actuator and a method for manufacturing an inkjet head using a single-crystal piezoelectric film or a single-orientation polycrystalline film. As a method for manufacturing a large-area / long actuator and an inkjet head, a method is generally used in which a piezoelectric film is directly formed on a diaphragm structure and then processed / molded to manufacture a device. In some cases, the piezoelectric film having desired characteristics cannot be formed due to the lattice constant and the coefficient of thermal expansion. The present invention is a manufacturing method that solves the above problems, and can apply a piezoelectric film having desired characteristics to a large-area and long-sized device. An object of the present invention is to solve the above problems, and to provide an actuator and an inkjet head having a large area and less variation in characteristics by a manufacturing method thereof. These are suitably used for microphones, sounding bodies (speakers, etc.), various vibrators / oscillators, and further acceleration sensors, pressure sensors, vibration sensors, angular velocity sensors, etc., in addition to inkjet heads.

[0007]

A method of manufacturing an actuator according to the present invention is an actuator for manufacturing an actuator by bonding a piezoelectric film formed on a single crystal substrate to a diaphragm structural member and then removing the single crystal substrate. A manufacturing method,
The single crystal substrate is a substrate having a bonding portion in which a plurality of single crystal substrates are bonded to each other. Further, the single crystal substrate in which the width of the bonding portion is 3 μm or less may be used. Further, the surface roughness Ra of the single crystal substrate measured through the bonding portion may be 15 nm or less. In addition, the two peak positions by rocking curve measurement in XRD (X-ray diffraction) are from 0.05 °
Single crystal substrates separated by 0.3 ° are preferred. Further, the single crystal substrate may be any one of a MgO substrate, an STO substrate, a BaTiO ₃ substrate, a Y or a ZrO ₂ substrate which may be doped with a rare earth element. Further, the thickness of the single crystal substrate may be 0.05 mm to 2.5 mm. A method for manufacturing an inkjet head according to the present invention is a method for manufacturing an inkjet head by removing a single crystal substrate after bonding a piezoelectric film formed on a single crystal substrate to a diaphragm structural member. Is a substrate having a bonded portion in which a plurality of single crystal substrates are bonded to each other. Therefore, according to the manufacturing method of the present invention, it is possible to manufacture a piezoelectric actuator and an inkjet head having high density, long length, and good characteristics. Further, the manufacturing method of the present invention can select a piezoelectric film having good piezoelectric characteristics using a single crystal substrate, and can be applied even if the device size increases.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The manufacturing method of the present invention includes a step of bonding a plurality of bonded piezoelectric films on a single crystal substrate to a diaphragm structure and a step of removing the single crystal substrate. . The manufacturing method of the present invention includes a step of forming a piezoelectric film on a single crystal substrate, a step of bonding the piezoelectric film to a diaphragm structural member, and a step of removing the substrate. FIG. 1 illustrates the process of the present invention. FIG. 1A shows a state in which a piezoelectric film is formed on a substrate. (b) shows a state in which the piezoelectric film is patterned according to the need of the device. This step is not essential, but it is a preferred mode for making an inkjet head into a device. (C) shows a state in which the patterned piezoelectric film is bonded to the diaphragm structural member. Is a joining layer used for joining and is mainly made of a metal material. (D)
Is a state in which the substrate is removed after bonding.

The substrate used in the present invention is a single crystal substrate, such as MgO, STO (SrTiO ₃ ), BaTiO ₃ ,
A ZrO ₂ substrate or the like which may be doped with Y or a rare earth is used. As rare earths, Pr, Nd, Eu, Tb, Dy, Ho, Yb ,,
Sm, Gd, Er, La etc. The preferred crystal plane is (10
0), (111) or (101). Preferred substrates are MgO substrates, STO substrates or doped ZrO ₂ substrates. Further, the substrate used in the present invention is one in which a plurality of substrates are joined. Therefore, when the rocking curve is measured by the XRD measurement, one or more peaks different from the main peak by several degrees are measured. Particularly, in the rocking curve measurement of the single crystal substrate used in the present invention, the positions of the main peak and other peaks differ from each other by 0.05 ° to 0.3 °. On the other hand, only one peak is observed in a single plate single crystal substrate (a peak may appear at a position separated by 10 ° or more from the main peak in a substrate with poor single crystallinity), but the present invention. Such an XRD peak is observed because the substrate has a slight misorientation at the bonding surface. In the rocking curve measurement of the single plate single crystal substrate to be joined,
The deviation of the position of the peak is preferably 0.3 ° or less. Even though there is such an azimuth deviation of several degrees, the piezoelectric film formed thereon has not only good characteristics but also this azimuth deviation. Therefore, even when a large area film is formed, the stress in the film may be appropriately dispersed and a uniform piezoelectric film may be formed. The film thickness of the substrate used in the present invention is 0.05 mm to 2.5 mm,
Preferably, it is 0.1 mm to 1.2 mm. When the film thickness of the substrate is less than 0.05 mm, it is not preferable because the flatness is difficult to be maintained and the strength is poor when the substrate area is large (for example, 500 mm ² or more). If the flatness is not maintained, it becomes difficult to form a good piezoelectric film when forming the piezoelectric film on the single crystal substrate. Also, the film thickness is 2.
If it exceeds 5 mm, it is not preferable because the workability is poor when removing the substrate in the process of manufacturing the actuator or the inkjet head.

An example of the method for producing the substrate used in the present invention will be described. FIG. 2 illustrates a process of making a substrate. FIG. 2 (a) is a stack of four single crystal bulk bodies, and the surface of the single crystal body at each contact surface (a) is polished. By subjecting this to high temperature under pressure,
It becomes the joined body of (b). (B) is a joint. This joint portion (b) can be optically recognized. By cutting the single crystal body thus bonded, a large-area single crystal substrate (c) having a bonding portion used in the present invention can be obtained.

In order to obtain a device having good uniform piezoelectric characteristics in the device fabrication in the next step, it is preferable to use a bonding part (b) having a width of 3 μm or less. More preferably 2.2
μm or less. The width of the joint can be measured by SEM observation. The presence or absence of the bonded portion can be confirmed visually or by an optical microscope from the difference in the refractive index of the bonded portion of the single crystal substrate or from the lattice mismatch. When the surface roughness is measured so as to traverse this junction, the Ra of the preferred substrate used in the present invention is 15 nm or less, more preferably 10 nm or less. The measuring method is, for example, Tencor P-10 manufactured by KLA Tencor, with a probe pressure of 5 mg and a scanning speed of 5 μm /
Second, 300 μm across the junction at a data acquisition frequency of 500 Hz
By measuring the length. If the width of the junction exceeds 3 μm or if Ra exceeds 15 nm, the crystallinity of the piezoelectric film in the substrate becomes poor, and it becomes difficult to obtain a device with good uniformity when used as a device.

In the next step, a piezoelectric film is formed on the surfaces of the bonded single crystal substrates. The piezoelectric film used in the present invention is a single crystal film or a single oriented polycrystalline film. A single-oriented polycrystalline film means that when measured by the XRD method (X-ray diffraction method),
The piezoelectric film has a specific peak intensity film of 90% or more,
It is preferably at least 95%. The crystal structure of the piezoelectric film is
It is a tetragonal crystal, a rhombohedral crystal, or an orthorhombic crystal. Preferred crystal orientations are <001> and <111>.

As a method for producing these piezoelectric films,
The sintering method, the sputtering method, the MBE (molecular beam epitaxy) method, the MOCVD method, the sol-gel method, the gas deposition method, the hydrothermal method, and the like are preferable, but the sputtering method, the MBE method, and the MOCVD are preferable.
Method, sol-gel method, hydrothermal method. The thickness of the piezoelectric film formed on the substrate is 0.8 μm to 50 μm, preferably 1.0 μm to 10 μm. If it is less than 0.8 μm, the displacement force as an actuator is poor and a sufficient force for displacing the substrate 2 cannot be produced. On the other hand, if the thickness exceeds 50 μm, the rigidity of the piezoelectric film itself increases, the displacement cannot be increased, and the driving voltage increases, which is not preferable.

The piezoelectric film used is lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZ).
T), lead magnesium niobate, lead magnesium niobium titanate, lead zinc niobate, lead zinc niobate titanate and the like. A small amount of dopant may be added to these materials.

Although the patterning of FIG. 1B is not an essential step, it is a preferable mode when a long ink jet head is manufactured, and a material having different coefficients of thermal expansion between the piezoelectric film and the diaphragm structural member is used. It can be stably made into a device. As the patterning method, wet etching, dry etching, resist lift-off, a method using a metal mask, or the like is used.

As a method for joining the piezoelectric film and the diaphragm structural member, a joining method such as direct joining, diffusion joining, an active metal method, or pressure welding can be adopted. Preferably, the active metal method, as the metal used, In, Pd, Au, Cr, Ni, Cu, Sn, M
Metals such as o, Ti, Zr, Ag and Pb can be used. The temperature at the time of joining is from 80 ° C to 500 ° C, more preferably from 100 ° C
It is 300 ° C. The pressure applied is 0.5 kg / mm ² to 20 kg / mm ² , preferably 0.8 kg / mm ² to 5 kg / mm ² . The layer used for the bonding layer by the active metal method may be used as the electrode. Further, as the direct joining method, for example, "Science Technical Report US95"
-24, EMD95-20, CPM95-32 ”.

The diaphragm structural member of the present invention is a workable substrate (including a laminated body) or an already processed diaphragm prepared. The diaphragm structural member is preferably the former. Materials used for the diaphragm structural member are metallic materials such as Si, SUS, Ni and Ti, and ceramic materials such as zirconia, alumina and glass. Preferably, it is a metallic material, more preferably Si.
It is a material. In particular, a Si substrate having a crystal orientation of {110} is preferable. As the Si substrate, an SOI substrate, an SOS substrate or the like may be used.

As a method of removing the substrate, there are a wet etching method and a peeling method. The wet etching method is a method of dissolving and removing the substrate using a liquid medium in which the substrate dissolves. The peeling method is preferable because the substrate can be reused. Examples of the peeling method include laser light peeling, water jet method, and mechanical peeling. Among them, laser light peeling and mechanical peeling are preferable. Laser peeling is a method of peeling a piezoelectric film from a single crystal substrate by irradiating the piezoelectric film interface with laser light and utilizing thermal decomposition due to a rapid temperature rise or a difference in coefficient of thermal expansion between the substrates. The laser used is an excimer laser, a YAG laser, a He-Ne laser, a gas laser, a semiconductor laser or the like. The mechanical peeling is a method of peeling by utilizing a physical mechanical force, and is a method of peeling the substrate by applying a mechanical stress between the substrate and the piezoelectric film.

In the method of manufacturing an ink jet head of the present invention, a pressure chamber, an ink supply path communicating with the pressure chamber, and a nozzle portion to be an ink discharge port are formed in an actuator obtained by the same method as the above method. Is. Figure 3
The process of making an inkjet head is illustrated in FIG. Figure 3
(a) is the actuator described in FIG. 1 (d),
An ink chamber is created in this (FIG. 3B). Is an ink chamber partition wall. As a method for forming the ink chamber, there are a method of forming an ink chamber by etching a Si substrate, a method of joining with a substrate on which an ink chamber is formed, or a method of forming an ink chamber partition wall by film formation. You may take the method. Is a diaphragm of the inkjet head and a lower electrode (not shown), and has a thickness of 0.5 to 15 μm, preferably 1 to 5 μm. In order to uniformly leave such a thin film by wet etching, it is preferable to use an SOI substrate as the diaphragm structural member. Also, the ink chamber may be created by dry etching. FIG. 3C shows an inkjet head in which a member having a nozzle portion is joined to an actuator portion having an upper electrode and an ink chamber. The member forming the nozzle portion may be a single-layer substrate or a multi-layer substrate.

Further, the manufacturing method of the present invention uses C on the piezoelectric film.
A manufacturing method in which a metal film such as r or Ni is formed and these are used as an electrode and a diaphragm may be used. In this case, the thickness of the metal diaphragm is preferably 0.5 times to 2.0 times the thickness of the piezoelectric film. When such a method is adopted, as the diaphragm structural member, a member having no portion corresponding to the diaphragm can be used.

The ink jet head obtained by the present invention can easily and stably obtain a unimorph type bender type head, but the diaphragm structural member is used as a shim and the piezoelectric film is bonded to both sides of the diaphragm structural member. Then, a bimorph type inkjet head may be created.

The present invention will be described below with reference to examples. (Example 1) 10 mm × 100 prepared by joining and cutting 10 cubic SrTiO ₃ (100) single crystal bulk bodies each having a side of 10 mm
mm STO (SrTiO ₃ ) substrate (thickness 0.15 mm, joint width
A PZT (001) film was formed to a thickness of 2.5 μm by sputtering on the surface roughness Ra of 5 μm (1.2 μm). PZT film is [00
It was a single crystal film oriented in the 1] direction. In the rocking curve measurement of this bonded STO substrate by XRD measurement, a peak was confirmed at a position deviated from 0.13 ° to 0.16 ° from the main peak. After forming a Ti layer (20 nm thick) on the PZT film on the STO substrate, an Au layer (200 nm thick) was formed to form a bonding layer. These were wet-etched to a density of 180 dpi. The size of one element of PZT after etching is 88μ in width.
This PZT element is 680 m long and 2.8 mm long on an STO substrate.
Books are lined up. Cr (30 nm) as a bonding layer on a SOI substrate (Ra = 0.02 μm,) with a Si (110) layer of 3 μm B-doped Si layer and 0.5 μm SiO 2 layer and a thickness of about 400 μm as a diaphragm structural member , Au (200 nm) was deposited. PZT
The upper Au layer and the Au layer on the SOI substrate were superposed and bonded by heating at 150 ° C. for 1 hour under a reduced pressure of 10 ⁻³ Pa and a pressure of 0.3 kgf / mm ² . The PZT film was bonded to the Au layer on the SOI substrate with good adhesion. When this was irradiated with excimer laser light (KrF) from the STO substrate side at a dose of about 350 mJ / cm ² , the STO substrate and P
The ZT was peeled off, and the PZT patterning body could be transferred onto the SOI substrate. When the upper electrode was made of Au paste and the Pr of the piezoelectric film after bonding was measured, it was a good characteristic of about 40 μC / cm ² . By wet etching using the SiO2 layer as an etch stop layer from the side opposite to the piezoelectric film of the Si substrate,
An ink chamber having a width of 100 μm and a length of 2 mm was formed under each piezoelectric film to obtain an actuator according to the present invention. 25 to this
A Si substrate with a nozzle of μmΦ opened and two SUS substrates with ink channels formed on top of each other were laminated to obtain an ink jet head with the nozzle portion at the end of the ink chamber. When the liquid is ejected at 5 kHz from now on, a droplet of about 20 pl will be discharged at 15 m / s
It was possible to discharge at the speed of.

Example 2 A piezoelectric film patterning body was prepared in the same manner as in Example 1 except that the thickness of the piezoelectric film was 4 μm, and the piezoelectric film was simultaneously bonded from both sides of a Ti substrate having a thickness of 20 μm. Then, the STO substrate was peeled off to obtain a bimorph type actuator. Example 1 using a Ti substrate as an electrode and applying the same potential to the piezoelectric films on both sides
When the amount of displacement was measured by a laser displacement meter in the same manner as in, a displacement of 1.25 μm at 1 kHz and 0.45 μm at 10 kHz was measured. In addition, there was little variation between the elements and good characteristics were shown.

Example 3 Bonded MgO substrates (thickness 0.5
mm, the width of the junction is 400 nm or less), PbTiO3 is deposited on
A single crystal film of ZT was formed. The misorientation of the MgO substrate in this case was confirmed by observing two peaks different from each other by 0.13 ° in the rocking curve measurement (see FIG. 4).
The film quality of PZT on this substrate was a single alignment film having a peak intensity ratio of 98% or more as determined by XRD measurement (θ-2θ measurement).
Then, Example 1 was performed except that the PbTiO3 layer was removed by etching.
When an actuator was produced by the same method as in (1), an actuator with similarly good characteristics was obtained. Moreover, when the piezoelectric film was formed on a substrate having a misorientation of 0.31 ° in the rocking curve measurement, the film quality of PZT was 90% of a single alignment film, but the characteristics of the manufactured actuator were slightly Although the displacement amount of was inferior, it was a practical displacement. (Example 4) An inkjet head was prepared in the same manner as in Example 1 using a STO substrate having Ra of 16 nm or more. As a result of the same evaluation as in Example 1, the ejection variation among the nozzles was slightly large, but excellent liquid ejection ability was confirmed.

(Comparative Example 1) An ink jet head having the same specifications as in Example 1 was used by using 10 STO substrates each having a side of 10 mm. A PZT (001) single crystal film was formed on each substrate by sputtering to a thickness of 2.5 μm and made into a device. As a result, a head could not be created at the joint between the substrates,
The head did not have a continuous array of nozzles at 180 dpi. Moreover, since the film thickness of the piezoelectric film is slightly different for each substrate, the ink ejection capacity is different for each substrate position,
It became a device that was difficult to control with different liquid volumes and droplet discharge rates.

[0026]

As described above, the present invention has the following effects. The manufacturing method of the present invention has an effect that a piezoelectric actuator and an inkjet head having high density, long length, and good characteristics can be manufactured. Further, the manufacturing method of the present invention has an effect that a piezoelectric film having good piezoelectric characteristics can be selected by using a single crystal substrate and can be applied even if the device size becomes large.

[0025]

[Brief description of drawings]

FIG. 1 is a diagram showing steps of a manufacturing method of the present invention.

FIG. 2 is a diagram showing a manufacturing process of a substrate of the present invention.

FIG. 3 is a diagram showing a manufacturing process of the inkjet head of the present invention.

[Fig. 4] Orientation shift of MgO substrate is measured by rocking curve.
It is a figure which shows that the peak of (400) was confirmed by observation of two peaks which differ from each other by 0.13 °.

[Explanation of symbols]

1 substrate 2 Piezoelectric film 3 Vibration plate structural members 4 Bonding layer 5 ink chamber 6 ink chamber partition 7 Inkjet head diaphragm 8 nozzle 9 Upper electrode B contact surface B joint Ha single crystal substrate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ken Matsuda             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Akio Ikematsu             2-6-2 Rokuno, Atsuta-ku, Nagoya-shi, Aichi             107 F term (reference) 2C057 AF93 AG82 AP14 AP23 AP24                       AP33 AQ10

Claims (7)

[Claims] 1. A method of manufacturing an actuator, wherein a piezoelectric film formed on a single crystal substrate is bonded to a diaphragm structural member, and then the single crystal substrate is removed to manufacture an actuator. A method for manufacturing an actuator, which is a substrate having a bonded portion in which a single crystal substrate is bonded to each other. 2. The method of manufacturing an actuator according to claim 1, wherein the single crystal substrate having a width of the bonding portion of 3 μm or less is used. 3. The method for manufacturing an actuator according to claim 1, wherein a surface roughness Ra of the single crystal substrate measured through the bonding portion is 15 nm or less. 4. The single crystal substrate according to claim 1, wherein the two peak positions measured by a rocking curve in XRD (X-ray diffraction) measurement are separated from each other by 0.05 ° to 0.3 °. 4. The method for manufacturing the actuator according to any one of 3 above. 5. The single crystal substrate is MgO substrate, STO substrate, Ba
TiO ₃ substrate, Y or ZrO optionally doped with rare earths
_{2. The} substrate according to claim 1, which is one of _two substrates.
To the method for manufacturing the actuator according to claim 4. 6. The single crystal substrate according to claim 1, wherein the thickness of the single crystal substrate is 0.05 mm to 2.5 mm.
A method for manufacturing the actuator according to any one of 1. 7. A method for manufacturing an inkjet head by bonding a piezoelectric film formed on a single crystal substrate to a diaphragm structure member, and then removing the single crystal substrate to manufacture an ink jet head. 2. A method for manufacturing an inkjet head, wherein the single crystal substrate is a substrate having a bonded portion bonded to each other.